Two-cycle internal-combustion engine



May 7, 1 929. w. a. sANDs Two-oww INTERNAL coMBsTIoN ENGINE .Filed Feb.- 29, 1928 4 sheets-sheet 1 W am Walir .B'and JG-l,

May 7, 1929. w. B. SANDS TWO-CYCLE INTERNAL COMBUSTION ENGINE Filed Feb. 29 ,l 1928 4 Sheets-Sheet 2 gmmnfor MHH' Bands ini May 7, 1929.

v w. B. sANDs 1,711,906

TWO-CYCLE INTERNAL COMBUSTION ENGINE Filed Feb. 29, 1928 4 Sheets-SheenI 3 f Mler .5. Sands @Hamas A May 7, 1929. w, B, SANDS 1,711,906

TWO-CYCLE INTERNAL COMBUSTION ENGINE Filed Feb. 29, 1928 4 Sheets-Sheet I 4 Patented May 7, 1929.

vomiten STATES l PATENT oFFicE'.

WALTER B. SANDS, o-iiY eHINooK, MONTANA.

v-'IVVO-{CYCLE INTERNAL-COMBUSTION ENGNE.

Appli-cation led February 2 chamber and the cylinder` walls, during com# bustion protected from the flames of combustion by an air curtain thereby conserving the heat for useful work and reducing the ill results of radiation. `By further reducing radiation by insulation of the chamber walls by air slots parallel with and adjacent tol the chamber walls. By so disposing the workingy parts that no valves are connected `with the working cylinder r at the time of combustion. y *Y v By eliminating` allvalves this superheated walls presenting a uniform andunbroken chamber wall, thereby permitting higher temperatures in the working chamber. In,- troducing the fuel and Y discharging the burned gases uniformly around the cylinder wall thereby equally heating all corresponding parts or' the cylinder and piston wall.

By presenting a comparatively thin combustion chamber wall thereby 'facilitating rapid changes oic temperature with a mini-r nium of'lieat losses. vBy thoroughly and promptly scavenging thecombustion chamber after each working stroke. By eliminatingall gears.V By effecting a high compres.- sion in` the ignition tube in a very simple Vandeffective manneiggcapable of variation automatically or mechanically tobest meet requirements. By automatically timing the ignition in a most simple manner7 reasily laltered .mechanically when-starting.` By reducing the weight and cost per horsepower withoutfsacriflce of stability. kg By reducing the number and speed of vfrictiona'l parts. By permitting the starting of the engine on low pressure therebyevercoming much of the'difficulty in starting mosthigh pressure engines. n Y

@ther advantages of construction will ap- Jear as -the engine andk its working Dartsare hereafter explained.

9,v 1928.l Serial No. 257,909.

Another verv `important object'of the invention resides in theprovision of an'. engine wherein the various parts for carrying out the two cycles are so .inter-related `and constructed as to cause vthe .engine'to run `in a smooth and. reliable manner.'V

l/Vith the above and numerous other ob.-k jects in View as will appear asthe description proceeds, the invention resides in cerl tain novel rfeatures of construction; and. in the combinationand arrangementjof parts as will be hereinafter morey fully described'and claimed. Y

In the drawing: v Y- Figure l is a. vertical vsection throughan engine embodying tliejfeatures of my invenktionfshowing the same about to iirej Figure 2 is a similar view. showing the main piston at the end of its powerstroke, l Figure 3V isa similar `view showing: the loose auxiliarypiston at the end of'its down# ward stroke, V l

Figure 4 isa top plan view-of the engine,` Figure 5 is a fragmentary side elevation showing the mechanism mounted on the head l of. the engine; c Figure 6-is a vertical section therethrough, Figure 7 is a transverse section ltaken substantially on the line'7'-7 of Figure 1,-and Figure 8 is a .diagrammatic view showing a check mechanism which may'beusedl in conjunction with the auxiliary loose piston? Referring .to thedrawings in detail,v it will be seen that'tlie'numeral 5 denotes the 'crank case with acylinder 6 rising therefrom. The upper end of the cylinder()l mergesinto reducedy cylindrical extension 7 by means of a shoulder 8.r head 9 is bolted orv other-. wise secured on. the upperend of the eXten-' sion 7. A power piston 10 is mounted for reciprocation in the cylinder fand the head of this piston yhas Va plate 11 mounted there# on held in spaced relation theretov by spacing Istuds-12 or in any otherfsuitable manner vso as to forman air pocket 13 therebetween. v.

At the periphery'otthe plate 11 there are irovided kopenings 14- communicatinfr'with i i :a n f kthe air pocket A loose piston 15 includes a head 16y with.. an annular-.space between it and the cylinder walls for reciprocation in reciprocation in the cylindrical extension Z Ther shank 1.7- is provided withl a! longitudi-v nally extending central bore 18 in which is the `cylinder 6 and a reduced" shank'l? for` located an elongated compression piston 19 and a floating piston 20. The here 18 is reduced in diameter at its lower end as is indicated at 18 and merges into a passage 21 leading from the head 1G.

The piston 20 is formed with a longitudinally extending lfuel conducting bore 22.

The bore 22 adjacent its lower end is provided with a cone shaped enlargement 24 in which is movable a cone shaped valve 25 which when raised closes oli the bore.

The shank 17 is formed in its lower portion with a cylindrical chamber telescopically receiving a cylinder 29.

.The shank 17 is provided with a longitudinally extending` passage 81 communicating with the cylindrical chamber 28 and extends upwardly for communication with a chamber 84 formed by wall 29 through a port in a plane 8G slidable in the head 9.

An abutment 37 extends around the piston 19 into the chamber 34. A transverse radial passage 38 extends from the lower portion of the bore 18 through the exterior of the shank and is closed atits inner ond by the floating piston 2O and the wall of the Vcylin der 7 when the parts are disposed in the position shown in Figure 1 ready to lire.

The shank 17 is provided with a longitudinally extending channel 39 constituting its outer'wall in communication with a valve conduit 40 leading through the cylindrical extension 7 immediately above the shoulder 8 and having a check valve 41 therein. his pipe 40 leads from a suitable source of coinpressed air. The piston head 16 is formed with passages 42 leading from the top thereof downwardly and then inwardly toward the center and then terminating adistance from the center. The cylinder 6 is 'formed in its upper part with anannular air chamber 43 opening` interiorly of the cylinder at the top thereof. An exhaust manifold 44 is disposed about the intermediate portion of the cylinder 6 communicating with ports 45 in. the cylinder which are closed by the apron 46 of the piston 10 when in a raised position and are open to the interior of the cylinder when the piston 10 is at the end o13 its power stroke as shown in Figure 2. e A connecting rod 47 from the piston 10 is engaged with a crank ot a crank shaft 48 rotatable in the crank case 5.

The. compression piston 19 extends through an opening'in the head 9 and terminates a distance thereabove. Clamp blocks 50 are disposed one on each side of the upper end of the piston 19 and have links 51 leading inwardly therefrom and connected to levers 52 roekabl'e in bracket 53 so that when the lever is turned in one direction the blocks are clamped on the piston 19 to hold the saine and when turned in an oppoite direction the blocks are released thererom.

The lever 52 is operated by a crank 54 leading therefrom and 'terminating in a piston 55 operating 1n a cylinder 5G on a cylin- Vder 57 the upper end oi which is closed by a valve 58 and in which extends a plunger 59 which plunger extends upwardly Jfrom the plate 86. An tube G1 dependiiig therefrom through-an opening in the valve 58 and a spring 62 is disposed about the tube G1 impinging against a oulder G8 on the end thereof and the valve 58 to normally hold'the valve closed. A tube 64 leads upwardly from the tank and has a valve 85 therein.

The lever 52 is connected by an arm 75 linked to a lever76 pivoted at 77 having an eccentric around the pivot which enters the groove 78 in the extended portion of the cylinder wall oit the shank 17 and preventing the piston 15 from following piston 10 as it starts downward. rllhe air exhausting through valve 65 releases the piston 55 restoring the levers 52 and 7 6 to normal. position thereby simultaneously locking piston 19 and releasing shank 17 and piston 16. Both pistons are free vto'move upward at any time. The shank 17 has an arm rigidly attached at right angles extending out and then downward to constitute a dash pot with a crank rod extending Vupward from the main crank shaft as shown Figure 8. A'

71u66 extends laterally from the plate 36 and is adapted to be engaged by the upper end of the shank 17 clearly indicated in Figure 7. The tank-80 is .supported by suitable brackets 67.

In considering the operation of the engine, I will start with Athe parts disposed expansion tank 69 has a as illustrated in Figure 1 wherein the exi plosion is taking place in vbore extension 18 and conduit 21 cansino the air and eas e e there meetin@` under high arcssure to 15J-nite. C Having reached the-highest point tne nston n o A n s 10 moves downwardly and the p ton 16 1s held'from ollowi'no and is soon moved u wardly assuming the position shown in Figure 2.

When the piston 10 reaches Vthe bottom of its power stroke the burnt gases are tree to exhaust out through port-s into' the exhaustA manifold 44. As the piston head-16 moves upwardly from the begi -ning ont the compression stroke it compresses' the air hetween the top Asurface thereotl and the shoulder 8 and part of itcntersthe passages/l2.

Then the piston 10 reaches the end o13 its worl'iing stroke and uncovers the port 45 Vthe Y pressure in the main cylinder is relieved and piston 16 is driven downward by gravity, by the pressure in chamber 28 and by the auxiliary pressure through conduit 44G`v as soon as channel 39 reaches the shoulder oi the main cylinder.V The compressed air entering through conduit 40 flows downward between the walls ot piston 1G and the main cylinder and being in such close contact cools the walls of both kescaping through port 4-5 until piston. 10 in its yupward stroke closes that port. When the small tube 22 which unites with the air driven from the chamber 88 this commingled gas and air is -precipitated against the upper face of piston and there beinel no esca Je of this .airl and gas being of a pressure sufficient,toigniter it is fired.

As soon as piston 10 reaches its highest vpoint and piston 16 is held from'following v it down around its sides to the face of -piston 10 and inward to meet the outwardl iiowing fuel from conduit 21. At this meeting point the combustion takes place but so long piston 16 moves upward there will be anair curtain around the sidesv ofthe walls of cylinder 6. VThe heat from the combustion radiating through theface of the piston16 to the air in channel 42 will expand it and force more air around the piston to the combustion chamber. v .i Y

rWhen piston 10 reaches the lower end'of its working stroke it uncovers'port 45 and,

the pressure in the main cylinder. isrelieved. Thereupon the piston 16 is driven-:down by gravity, bythe compressed air in the chamber 8O and yafter the. channel 39 passes the shoulder of the'main cylinder by the compressed air coming infthrough conduit 46' and channel 39. Thiscompressed air flows throughfthe annular passage between the walls of piston 16 and the main cylinder walls and being in close contactl tends to cool both in a most eiiicient manner.

AIt will be further seen that as piston 19 is s held in place at its highY point the descent of the shank 17 enlarges the chamberin which is the floating piston 20tending 4to create a vacuum but at this time fuel is forced in through conduit 22 under a pres-- surevapproximately equal to the pressure in the auxiliary air. supply in conduit 4() thereby forcing the floating piston upward in proportion to the amount of fuel admitted.

Someburnt gases may, where the fuel feed `is light, enter the chamber 178 *fromY below. but the channel 68 will soon be uncovered .at both ends and as the compressed airthrough conduit entering above piston16 will have a greater pressure than 4the pressure in the main cylinder at the lower end of bore 21 the freshl air will flow through `58 to the lower side of the floating piston and the oati'ng piston, having only a small passage through it will establish itself at equilibriumand serve as a dividingwall between the gas labove and theairlbelow it; This lequilibriuin will be maintained at all times by the floating piston.. Itis presumed the fuel will gasify from the heat in the chamber walls as soon as `it entersbut it vwill start with `liquid fuel under extraV high pressure. e v Y OnA the .compression stroke approximately the. same pressure is generatedin the cylinder 18 as in the main cylinder andzwhen the outer endv of the channel 38 reaches the shoulderI of the main'cylinder itis closed and at about the same timev the other end of 38 is closed by the floating piston,

Also on the compression stroke pressure is generated in chamber28 but the initial pressure therein is vat or'below atmospheric Aand it4 has a greater clearance space greater than inthe main cylinder, therefore, it does not reach as .high a Acompression asl in themain cylin der. is automatically.controlled with cert-ain degrees by a sliding valve 36 working in a por-- It vhas at a lpoint near the top a passage through it to register with a passage' through The compression in chamber 28V 100 the stationary wall?. The stationary strucf ture 7 forms the'f'outer wall of the cylinder -l 34. l The piston therein isa lateral extension of the piston19. AThe chamber 34 is con- .nected by the conduit 78 to the atmosphere and remains at approximately. atmospheric pressure.

y'When the valve l36v moving upward through the Contact ofY pin 66 with the wall of the shank n'17 compresses the air in cylinder 62 and vthe communicating cylinder 56 sufficiently to release the piston 19 the airl pressure over the extension piston 87 having an exposed area several times as great as the `area'rof the piston 19 overcomes theupward f pressure of the ygas and air inthe iioating piston chamber and drives the piston 19 downward with great force .thereby compressing the gas and air on both sides of the iioating piston and driving bot-h gas and air through the respective passages 22 and 18 into thel conduit 2l. u The lower end of oon-l duit 2l being then closed bycontact with the ilo face of piston 10 nowbecomes an ignition chamber by reason ofthe high pressure of i the mixed gas and air therein.

As soon as the piston 10 starts downward it opens the conduit 2l and the ignited fuel rushes out between the faces of the pistons 10 and 16 toward the main cylinder walls.

But before this fuel reaches the cylinder walls it comes in contact 'with the compressed air rushing downward from the upper side of piston 16 and combustion takes place be- .fore the gas reaches the cylinder walls. The combustion between 'the piston raises the temperature .o'i the gases therein and moves the pistons apart. yThe upward movement of the piston 16 drives more air down around its sides to the point ot 'combustion in the interior oil the main cylinder. It will thus be seen that the downward flowing current of air around the piston 16 forms a curtain for the protection et the cylinder walls 'from the burning gases during the entire combustion period which will probably be about one eighth of the time of the working stroke.

As it will be desirable to deliver the fuel to the combustion chamber, the main cylinder, in a shorter time when the engine is running rapidly than when it is running slowly. The pressure above the extension piston 37 which is the same as the pressure in. chamber 28 and in the slot 3l, all being connected. The valve 36 is dropped when the wall of the shank l?" moves downward at the end of the power stroke. As this valvemoves by the' force ot gravity only it moves more slowly than shank 17, and registers its port with the port 3l opening into the chamber lelat a relatively later moment than when the pistons are moving slowly.

rlhe pressure in chamber 28 and slot 31 willy therefore be lower than if the registration had occurred before the piston 16 had so nearly reached its lowest point. lf the pressure in chamber 28 is at the time of registration below atmospheric there will be a 'How oi' air from chamber 34 to chamber 28 and the pressure in that chamber will be increased by the additional air therein at the Cfr , tion shown in next liring stroke. lf the registration is relatively early, that is if the pistons are moving rslowly and the valveV 36 follows the piston closely, the pressure in 28 will be high and air will liow out of that chamber to chamber lt should beobserved that if the piston i0 is moving slowly it will uncover the port 4J) slowly and release-the pressure in the maincylinder slowly and thereiore piston 1G will start downward slowly.

lli desired valves 'T2 may be provided in the shoulders 8 and operated by suitable mechanical mechanism' from .the crank shaft orautomatically so as topermit compression above the piston 16 when moving trom the position shown in Figure 2 to the positalce oit air on the scavenging stroke oit 'piston 16 through the valvesi't. l

Yiligure 1 and to allow the in-r mechanism comprises a dash pot with the plunger 'T6 therein carried by a stein .from the piston 15. The dash pot 75 has an air pipe utlet as atV Z8 valve control. The plunger is provided with a connecting rod 79 operable on the crank 8O ot' the crank lt is thought that the construction, operation, and advantages ci the invention will new be clearly understood by vthose skilled in this art without a more detailed description thereof.

rlhe present embodiment of the invention has been disclosed in detail', merely by way of example, since in actual practice it attains the features of advantages enumerated as desirable in .the ststeinenty offthe invention and the above description. V

It will be apparentthat changes in the details oit construction, and in the combination and arrangement of parts may be resorted to without departing Yfrom the spirit or `scope of the invention as hereinafter claimed or sacrificing any ot its advantages.

Having thus described my invention, what l claim as new is:

1. ln a two cycle internal combustion engine, a cylinder reduced to provide a. shoulder and a cylinder extension, a powerpiston in the cylinder, a loose piston in the cylinder having'a shank with a piston lit within the extension, said shank having a-longitudinally extending bore, a. pressure piston in the bore having a longitudinally exteifiding` conduit therein for connection with asource.`

oi' fuel, a check valve in the conduit, an abutment .projecting 'from the pressure piston, said shank having a con'ipartment in'which said abutment is operable, and means for creating an air pressure behind the abutment to cause compression by the pressure piston.

2. ln a two cycle internal combustion engine, a cylinder reduced to provide a shoulder and a cylinder extension, a power piston in the cylinder, a loose piston in the cylinder the extension,l said shank having a longitudinally extending bore, a pressure piston in the bore having a longitudinallyJ extending conduit therein for connection with Va source of fuel, a check valve-in` ne having a shank with a piston fit within'A close the floating piston over the transverse conduit and to cause compression by the pressure piston,

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3. In a two cycle internal combustion engine, a cylinder reduced toprovide a shoulder and a cylinder extension, a power piston in the cylinder, a loose piston in the cylinder thereto.

4t. Ina two cycle internal combustion engine, a cylinder reduced to provide a shoulder and a cylinder extension, a power piston in the cylinder, a loose piston in the cylinder having a shank with a piston fit within the extension, said shank having a longitudinally extending' bore, a pressure piston in the bore having a longitudinallyy extending conduit therein for connection with a source of fuel, a check valve in the conduit, and means forfcreating an air pressure to cause compression by the pressure piston, said cylinder having exhaust ports, a plate on the head of the piston in spaced relation thereto, said scavenging piston having conduits leading from the upper surface thereof downwardly and toward the center thereof, said shank having a longitudinally extending channel, said extension having an opening communicating with a source of air under pressure, the channel registering with the opening and adapted to be communicated with the cylinder when the .loose piston is part way downfso that Aa current of air will pass through the conduit in the loose piston for cooling purposes and air for a fresh charge in the cylinder.

5. In a two cycle internal combustion en gine, a cylinder reduced to provide a shoulder and a cylinder extension, a power piston in the cylinder, a loose piston in the cylinder having a shank with a piston fit within the extension, said shank having a longitudinally extending bore, a pressure piston in the bore having a longitudinally extending conduit therein for connection with a source of fuel, a check valve in the conduit, and meansfor creating an air pressure to cause compression by the pressure piston, said cylinder having exhaust ports, a plate on the head of the piston in spaced relation thereto, said loose piston having conduits leading from the upper surface thereof downwardly and to- Ward the center thereof, said shank having a longitudinally extending channel, said extension having an opening communicating with a source of air under pressure, the channell registering with the opening and adapted to be communicated with the cylinder when the loose piston is part way down so that a current of air will pass through the conduit in the loose piston for cooling purposes, and for changing the piston for a new explosion, thecylinder being provided with an annular air chamber; having openings leading interiorly of the cylinder at the upper end thereof to receive said air current asthe loose piston moves upwardly. i

6. In Va two-cycle'internal combustion engine, a cylinder reduced to provide a shoulder es,k

and a cylinder extension and having an exhaust, a power piston in the cylinder, a loosel piston in the cylinder with a space between it and the cylinder wall and having a shank with a piston fit within the extension, said shank having a longitudinally extending bore, pressure piston in said bore having a longitudinally extending conduit therein for connection with a source of fuel, a` check valve in the conduit, and means for creating an air pressure to cause compression by thepressure piston.

7. In a two-cycle internal combustion engine, a cylinder reduced to provide a shoulder and a cylinderl extension and having an exhaust, a power piston in the cylinder, a loose piston in the cylinder with a space between it and the cylinder wall for the passage of fluid and having ashank with a piston fit within the extension, said shank withv a longitudinal bore and an air passage, means for supplying fluid under pressure to said passage, a pressure piston in the bore having a longitudinalconduit therein for connection with'a source of fuel, and a check valve in the conduit.

8. In a two-cycle internal combustion engine, a cylinder reduced to provide a shoulder and a cylinder extension and having an exhaust, a power piston in the cylinder, a loose piston in the. cylinder with a space between it and the cylinder wall for the passage ofv fluid and having a shank with a piston fit n chamber in its wall between the shoulder and the exhaust and communicating adjacent to the shoulder with the'interior' of the cylinder.

In testimony whereof I affix my signature.

WALTER B. SANDS. 

